[Bug] Update requests should set first_execution_run_id

[dandavison]

Update requests do not send first_execution_run_id:

sdk-python/temporalio/client.py

Lines 5252 to 5285 in 0b327b0

	async def start_workflow_update(
	self, input: StartWorkflowUpdateInput
	) -> WorkflowUpdateHandle[Any]:
	# Build request
	req = temporalio.api.workflowservice.v1.UpdateWorkflowExecutionRequest(
	namespace=self._client.namespace,
	workflow_execution=temporalio.api.common.v1.WorkflowExecution(
	workflow_id=input.id,
	run_id=input.run_id or "",
	),
	request=temporalio.api.update.v1.Request(
	meta=temporalio.api.update.v1.Meta(
	update_id=input.update_id or str(uuid.uuid4()),
	identity=self._client.identity,
	),
	input=temporalio.api.update.v1.Input(
	name=input.update,
	),
	),
	wait_policy=temporalio.api.update.v1.WaitPolicy(
	lifecycle_stage=temporalio.api.enums.v1.UpdateWorkflowExecutionLifecycleStage.ValueType(
	input.wait_for_stage
	)
	),
	)
	if input.args:
	req.request.input.args.payloads.extend(
	await self._client.data_converter.encode(input.args)
	)
	if input.headers is not None:
	temporalio.common._apply_headers(
	input.headers, req.request.input.header.fields
	)

However, they should, and other SDKs do.

Also, is it correct that we don't use the run ID from the response when constructing the returned update handle?